Image 2: A still from a 9-frame series
at 0.1 millisecond intervals showing a Sphagnum moss capsule explosion.
Researchers used ultra high-speed cameras to reveal that each launch is
accompanied by a miniature mushroom cloud, indicating the formation of a vortex
ring. These rolling haloes of air give the spores the extra boost they need to
get high enough off the ground to catch the wind currents that carry them long
distances.
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About This Image
To reproduce, Sphagnum, a type of peat moss,
must disperse spores into the air that are carried by the wind over long
distances. But Sphagnum live as a flat mat low to the ground. So how do they
send their spores high enough into the air to what's called the "turbulent
boundary layer" (a zone 10 centimeters off the ground), where swirls of
air and sideways currents can carry the spores over long distances?
Whitaker and Edwards were awarded a
National Science Foundation major research instrumentation grant (grant DBI
07-22532) for Williams College to establish a high-speed imaging facility. The
facility enables researchers to view things in the natural world that occur in
the blink of an eye, like the strike of a mantis shrimp or the sprint of a
greyhound dog.
Whitaker and Edwards used the facility's
ultra high-speed cameras--which shoot up to 100,000 frames per second--to film
the firing of the spore cannons. They discovered that each launch is
accompanied by a tiny mushroom cloud. The clouds are actually rolling haloes of
air called vortex rings, that give the spores the extra boost they need to
reach the turbulent boundary layer.
To learn more about this research, see
the Discover Magazine story “Mosses use explosive cannons and mushroom clouds
to spread their spores.”
(Date of Image: 2010)
Credit: Joan Edwards
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